You said you are inserting records into your custom table from the bank account general entry table in your codeunit, if I understand you correctly, now you want certain fields in your custom table to be updated when you post the general entries?.. don't know where/when you are executing your codeunit, but it's important to note that the codeunit where you insert records from the bank ledger entry needs to be aligned with posting general entries.
Or else you have to manually modify your custom table in the specific event in Post codeunit
